Promise.resolve = function(item) {
    if(item && typeof item == 'object' && item instanceof Promise) {
        return item
    }
    return new Promise((resolve, reject) => {
        resolve(item)
    })
}

let promise = new Promise((resolve, reject) => {
    resolve('hhhhhh')
})

Promise.resolve(promise).then(res => console.log(res))